Lifestyle remains a major factor in disease prevention

We all know people who appear to have had a bad roll of the dice and developed cancer despite doing their best to follow the rules of healthy living with a balanced diet, exercise, not smoking and not drinking too much.

We all know people who appear to have had a bad roll of the dice and developed cancer despite doing their best to follow the rules of healthy living with a balanced diet, exercise, not smoking and not drinking too much.

It is believed that around four in 10 cancers can be prevented by lifestyle changes.

But the randomness of the disease in so many cases continues to leave us with questions.

When it comes to geographical variations in rates of different cancers across the country, there are certain conspicuous clues behind some of the patterns.

It is accepted that areas of deprivation feature higher rates of smoking, bad diet, alcohol consumption and obesity that contribute to the risk of developing the disease.

Lung, oesophageal, stomach, head and neck, kidney, bladder and cervical cancer all have a common risk factor in cigarette smoking.

Smoking is also a major factor in explaining higher rates of cancer in the urban areas of Dublin and Cork and in the most deprived geographic regions in Ireland.

The incidence of smoking-related cancers has fallen among men but lung cancer among women in Ireland is increasing.

The availability of Breastcheck in some areas of the country, such as Dublin, before it was extended to other regions, would also have led to a mini-spike in more breast cancers being diagnosed from 2000 onwards.

More Prostate Specific Antigen (PSA) testing and older age among men in western counties can also partly explain the higher rates of prostate cancer.

Many men with raised PSA levels do not have prostate cancer.

Some prostate cancers identified through testing are very slow growing, and may not require treatment.

But what role are our genes playing in all of this? How much of the lottery is beyond our control? A report by the cancer registries in the North and Republic of Ireland in recent years found a markedly higher risk of leukaemia in the Republic compared to Northern Ireland.

It recommended that areas of unexplained higher-than-average cancer risk should be studied in detail.

It found "largely unexplained geographical patterns" for some stomach, bowel and skin cancers.

The John Hopkins University School of Medicine recently added even more complexity to the mix.

It released a major study saying the majority of cancers are the result of bad luck rather than unhealthy lifestyles or inherited genetic faults.

But more research is needed.

One fact we are sure of is that incidence of cancer in Ireland will rise and projections are that it will double by 2040. The most rapidly increasing cancers are expected to be those of the skin - both melanoma and non-melanoma - in both sexes.

Although demographic change will be the main factor driving an increase in cancer numbers, other factors such as the extension of free screening for breast, cervical and bowel cancer will also have an impact.

There is no proven way to prevent cancer but we can reduce our risk. The best available advice we have to rely on for now is to try to obey healthy living guidelines, staying safe in the sun and never delaying getting symptoms checked.